/*-------------------------------------------------------------------------
 *
 * statistics.h
 *      Extended statistics and selectivity estimation functions.
 *
 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * This source code file contains modifications made by THL A29 Limited ("Tencent Modifications").
 * All Tencent Modifications are Copyright (C) 2023 THL A29 Limited.
 *
 * src/include/statistics/statistics.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef STATISTICS_H
#define STATISTICS_H

#include "commands/vacuum.h"
#include "nodes/relation.h"

#define STATS_MAX_DIMENSIONS    8    /* max number of attributes */

/* Multivariate distinct coefficients */
#define STATS_NDISTINCT_MAGIC        0xA352BFA4    /* struct identifier */
#define STATS_NDISTINCT_TYPE_BASIC    1    /* struct version */

/* MVDistinctItem represents a single combination of columns */
typedef struct MVNDistinctItem
{
    double        ndistinct;        /* ndistinct value for this combination */
    Bitmapset  *attrs;            /* attr numbers of items */
} MVNDistinctItem;

/* size of the struct, excluding attribute list */
#define SizeOfMVNDistinctItem \
    (offsetof(MVNDistinctItem, ndistinct) + sizeof(double))

/* A MVNDistinct object, comprising all possible combinations of columns */
typedef struct MVNDistinct
{
    uint32        magic;            /* magic constant marker */
    uint32        type;            /* type of ndistinct (BASIC) */
    uint32        nitems;            /* number of items in the statistic */
    MVNDistinctItem items[FLEXIBLE_ARRAY_MEMBER];
} MVNDistinct;

/* size of the struct excluding the items array */
#define SizeOfMVNDistinct    (offsetof(MVNDistinct, nitems) + sizeof(uint32))


/* size of the struct excluding the items array */
#define SizeOfMVNDistinct    (offsetof(MVNDistinct, nitems) + sizeof(uint32))

#define STATS_DEPS_MAGIC        0xB4549A2C    /* marks serialized bytea */
#define STATS_DEPS_TYPE_BASIC    1    /* basic dependencies type */

/*
 * Functional dependencies, tracking column-level relationships (values
 * in one column determine values in another one).
 */
typedef struct MVDependency
{
    double        degree;            /* degree of validity (0-1) */
    AttrNumber    nattributes;    /* number of attributes */
    AttrNumber    attributes[FLEXIBLE_ARRAY_MEMBER];    /* attribute numbers */
} MVDependency;

/* size of the struct excluding the deps array */
#define SizeOfDependency \
    (offsetof(MVDependency, nattributes) + sizeof(AttrNumber))

typedef struct MVDependencies
{
    uint32        magic;            /* magic constant marker */
    uint32        type;            /* type of MV Dependencies (BASIC) */
    uint32        ndeps;            /* number of dependencies */
    MVDependency *deps[FLEXIBLE_ARRAY_MEMBER];    /* dependencies */
} MVDependencies;

/* size of the struct excluding the deps array */
#define SizeOfDependencies    (offsetof(MVDependencies, ndeps) + sizeof(uint32))

extern MVNDistinct *statext_ndistinct_load(Oid mvoid);
extern MVDependencies *statext_dependencies_load(Oid mvoid);
#ifdef __OPENTENBASE__
extern MVDependencies *statext_subset_load(Oid mvoid);
#endif

extern void BuildRelationExtStatistics(Relation onerel, double totalrows,
                           int numrows, HeapTuple *rows,
                           int natts, VacAttrStats **vacattrstats);
extern bool statext_is_kind_built(HeapTuple htup, char kind);
extern Selectivity dependencies_clauselist_selectivity(PlannerInfo *root,
									List *clauses,
									int varRelid,
									JoinType jointype,
									SpecialJoinInfo *sjinfo,
									RelOptInfo *rel,
									Bitmapset **estimatedclauses);
#ifdef __OPENTENBASE__
extern Selectivity subset_clauselist_selectivity(PlannerInfo *root,
									List *clauses,
									int varRelid,
									JoinType jointype,
									SpecialJoinInfo *sjinfo,
									RelOptInfo *rel,
									Bitmapset **estimatedclauses);
#endif
extern bool has_stats_of_kind(List *stats, char requiredkind);
extern StatisticExtInfo *choose_best_statistics(List *stats,
                       Bitmapset *attnums, char requiredkind);

#endif                            /* STATISTICS_H */
